A 2,000-year-long record of reproduction in Santa Barbara Basin benthic foraminifera

This dataset accompanies a submission to Proceedings of the Royal Society B entitled "A nineteenth and twentieth century reproductive regime shift in benthic foraminifera from the Santa Barbara Basin, California." The dataset includes measurements of individual reproductive life history traits for 20,293 individuals. Specifically, these are reproductive mode (megalospheric or microspheric, via the the size of the proloculus, or first chamber) and accumulation rate (a time- and area-normalized test count). Paper Abstract: Long-term records that span the past several centuries and capture within-population variation are critical for distinguishing ephemeral ecosystem changes from regime shifts. Using a ~2 kyr record of reproductive life history from the central Santa Barbara Basin, we examined population trends in reproductive mode and accumulation rate (i.e., reproductive output) across four species in the biserial benthic foraminiferan genus Bolivina. Bolivina populations were consistently dominated by asexually-produced individuals until the mid-nineteenth century, after which they exhibit an increase in variance and decrease in mean proportion of asexualy-produced individuals. At the same time, they rundergo an order-of-magnitude decline in accumulation rate. The magnitude and persistence of these changes suggests that the nineteenth and twentieth century represent a life history regime shift. Compounding effects of anthropogenic impacts and long-term trends in the California Current system (such as heightened deoxygenation and altered sedimentation regimes) may have pushed Santa Barbara Basin towards increased investment in sexual reproduction.本数据集配套提交给《英国皇家学会学报B辑》（Proceedings of the Royal Society B）的论文，题为《加利福尼亚圣巴巴拉盆地底栖有孔虫19至20世纪生殖模式转变》。 本数据集包含20293个个体的单个生殖生活史性状测量数据，具体为生殖模式（通过初室（proloculus，即首个形成的壳室）的大小判定为巨球型或微球型），以及累积速率（经时间和面积标准化的壳体计数）。 论文摘要：能够跨越数百年并捕捉种群内变异的长期记录，是区分短暂生态系统变化与模式转变的关键。我们利用圣巴巴拉盆地中部约2000年的生殖生活史记录，对双列底栖有孔虫玻瓶虫属（Bolivina）的4个物种种群的生殖模式与累积速率（即生殖产出）的变化趋势展开了研究。直至19世纪中期，玻瓶虫种群始终以无性繁殖个体为主；此后种群无性繁殖个体占比的均值下降，同时其方差升高。与此同时，其累积速率出现了一个数量级的下降。这些变化的幅度与持续性表明，19至20世纪发生了一次生活史模式转变。人类活动影响与加利福尼亚洋流系统的长期趋势（如加剧的脱氧作用与沉积模式改变）的复合效应，可能推动圣巴巴拉盆地的物种更多投入有性繁殖。